•pt- 9. 1875J 



NATURE 



395 



one or two " coaches " give also, but on a slip he has cor- 

 rected his printed answer. 



Again, in Ex. 27, p. 55 : "A balloon has been ascending 

 vertically at a uniform rate for 4*5 sees., and a stone let 

 fall from it reaches the ground in 7 sees. ; find the velocity 

 of the balloon and the height from which the stone is 

 let fall." Both Mr. Magnus and Dr. Wormell (" Natural 

 Philosophy," p. 129, Ex. 45) work this question as if the 

 balloon were at rest when the stone is let fall ; we see no 

 reason for their doing so in the wording of the question. 

 They give the same height for the balloon, but differ in 

 the velocity. 



OUR BOOK SHELF 



Game Preservers and Bi7-d Preservers. By Capt. J. F. 



Morant. (Longmans, Green, and Co., 1875.) 



To increase the annual rental of Scotch moorland, and 

 to feel certain that at least thirty brace of grouse will fall 

 to each gun after a whole day's sport, are the greatest 

 delights of a certain few, according to whom every other 

 consideration must be put in abeyance. Capt. Morant is 

 one of these. " The red grouse is about the best game 

 bird in the whole world, and deserves all the care we can 

 bestow upon him." This care involves the annihilation 

 of every creature that shows the least disposition to 

 destroy and feed upon the eggs, young, or adult of 

 La^opus scoiicus ; and the death-list is no small one, in- 

 cluding eagles, buzzards, hen harriers, all other Raptores, 

 ravens, crows, magpies, v/ild foxes, polecats, stoats, and 

 weasels. The stomachs of hawks are often found to con- 

 tain the remains of weasels and rats ; why kill them if 

 they destroy those vermin ? " If an alderman were ship- 

 wTCcked on an uninhabited island, he would probably live 

 upon the contents of a cask of biscuits which might be 

 washed ashore. But the scientific gentleman among a 

 party of savages who might examine him after his friends 

 who happened to land on that island had killed him for 

 their supper, would, we know, arrive at an erroneous con- 

 clusion if he entered it in his note-book as a fact that 

 the animal alderman lived entirely on dry biscuit." This 

 running analogy is the argument employed throughout 

 the book, and it is this which makes it a particularly 

 amusing one to glance through ; whether it carries con- 

 viction with it is a different thing. The grouse disease is 

 explained as depending on the fact that these birds, un- 

 like others, eat only one food, heather, and when this is 

 injured by cold or otherwise, they have no other to fall 

 back on. That many shot-damaged birds survive and 

 afterwards produce unhealthy offspring is considered un- 

 likely. " Can we fancy a grouse telling his mate on a 

 spring morning, My dear, I feel very poorly to-day ; that 

 No. 5 in my spine is troubling me dreadfully ? " The 

 author's raid against all the Raptores is very severe ; he 

 in this, as in other points, being much opposed to the 

 general tenour of the report of the evidence given before 

 the Parhamentary Select Committee appointed in 1873. 

 His considerable experience adds great weight to the 

 aspect of the question which he espouses. 

 The Handy-Book of Bees, being a Practical Treatise on 

 their Profitable Manage^tient. By A. Pettigrew. Second 

 Edition, revised and improved. (Edinburgh and Lon- 

 don : Blackwood and Sons, 1875.) 

 A Manual of Bee-keeping. By John Hunter, Honorary 

 Secretary of the British Bee-keepers' Association^ 

 (London : Hardwicke, 1875.) 

 These two volumes have different objects and will serve 

 different purposes. The first edition of Mr. Pettigrew's 

 book was favourably noticed in our columns five years 

 ago (Nature, vol. ii. p. 82), and we are glad to see that a 

 second edition has been called for. Still more pleased 

 are we to find that the author is open to conviction, and 



that he has acknowledged and corrected a few theoretical 

 errors in the first edition. For the economical manage- 

 ment of bees with a view to profit, there is no better 

 guide than Mr. Pettigrew. 



Mr. Hunter's volume, on the other hand, is essentially 

 a book for the amateur, to whom profit is of less import- 

 ance than the amusement and interest of bee-keeping. 

 He gives an account of all the appliances of the modern 

 apiarian, and of the most recent improvements in the 

 treatment and study of bees. The various kinds of honey- 

 extractors, feeders, guide-combs, and queen-cages ; the 

 methods of artificial swarming, queen-breeding, and 

 ligurianising ; the diseases and enemies of bees ; and the 

 various methods of preparing and preserving the honey 

 and wax, are all briefly discussed. Some of the most 

 recent observations on the habits and instincts of bees 

 are given, including Sir John Lubbock's interesting proof 

 that they distinguish colours. The book is illustrated 

 with a number of useful woodcuts, chiefly of hives and 

 apparatus ; and it will be indispensable to amateurs who 

 wish to acquaint themselves with the most recent improve- 

 ments in the art of bee-keeping, and the latest discoveries 

 as to the habits, instincts, and general natural history of 

 the honey-bee. A. R. W. 



LETTERS TO THE EDITOR 



[The Editor does not hold himself responsible for opinions expressed 

 by his correspondents. Neither can he undertake to return, 

 or to correspond with the writers of, rejected manuscripts. 

 No notice is taken of anonymous communications,'^ 



Personal Equation in the Tabulation of Thermo- 

 grams, ^c. 



In a late number of Nature (vol. xii. p. loi) you have com- 

 mented upon the work performed by the Meteorological Office. 

 Although in no way interested in the defence of that department, 

 I think objection may fairly be taken to the style ot criticism 

 adopted. Not onl)' would it, in most cases, be necessary to refer 

 to the original thermograms satisfactorily to detect the many 

 small errors pointed out, bat it is well known to practical men 

 that owing to certain idiosyncrasies of individuals some of the 

 numbers i, 2, 3 ... 8, 9, o do occur in estimations more 

 often than others, and of course more otten than they should 

 do theoretically. In no case are such personal peculiarities 

 likely to show themselves more than in the determination 

 of the position of a hazy photographic trace of sensible 

 breadth, as between two sharply defined lines. As an example 

 of my meaning, I may refer to somewhat similar estima- 

 tions of tenths of seconds, as tabulated by the highly-trained 

 and experienced observers of Greenwich, only premising for 

 the information of the uninitiated, that the tenth part of a 

 second is far too large a measure of time to be trifled with by 

 astronomers, and that practically the estimation is simply that of 

 the position of one sharply marked puncture or dot as referred to 

 two others equally well defined on either side of it, indicating 

 the beginning and end of the second, and separated by about 

 one-third of an inch. Referring to the Greenwich Observations 

 of 1864 (the only volume I have at hand), and taking three days' 

 observations at random for the experiment, I have determined 

 the percentage of times that each of the numbers i, 2, 3. ..8, 9, o 

 occur as the tenth at which transits of stars took place. As 

 there is no theoretical reason why one number should predomi- 

 nate over another, we may expect that the percentage for each 

 figure will be accurately 10, or each a tenth of the entire 

 number. 



The following are the percentages founded upon 511 estima- 

 tions on April 21, upon 379 on April 19, and upon 393 on 

 Nov. S, 1864, respectively : — 



